Bad Quality, Sony HDD, Exporting & a 1000 other questions...

Hello,
I'm a Mac noob and having adjustment issues.
1. I have a Sony DCR SR100 HDD Camcorder. Althought it records in mpeg2 it is compatible with iMovie 08 in that I can import directly from the camera.
Here is my problem, when I put the movie together, export to the media browser, and burn to iDVD, the video on the TV is lacking in quality. Seems a bit pixelated and not as clear as when I we using Adobe Premier on my PC.

I got streamclip and the Apple playback component so I can convert using that as well. Bottom line is that I want to burn all movies to DVD for the TV. Are there best settings I want to use for both import and export? Is there something I am doing wrong in iDVD?

I've got to run to go see DarkKnight so I'll start my question with those.
Thanks
~Peter